26. Tom notices that he is a lot more short of breath after he finishes a 200 meter sprint than when he jogs for 3 miles. He is confused because he feels as if he should feel more tired when he runs for a much longer distance. Explain to him why it makes sense that he is indeed more short of breath after running a sprint than jogging. Make sure to explain it using your scientific knowledge of cellular respiration.

Running a sprint will make you more tired than jogging a long distance because you will build an oxygen debt by using it aerobically. You use up a lot of oxygen fast because you need to make ATP faster when sprinting, then you would if you jogged a long distance. Jogging a long distance means you are making engery anaerobically. When sprinting, you will have to replenish the engery to pay back the oxygen debt.

27. A scientist isolates mitochondria form human cells and places them in an acid solution. The acid penetrates the intermembranous space of the mitochondria. The scientist then notices that the mitochondria start making ATP despite the fact that he is not providing any glucose for them. How is it possible that the mitochondria are still making ATP? (Think back to what an acid is, what it releases when placed in a solution and why this would make the mitochondria synthesize ATP).

An acidic compound increases the concentration of hydrogen ions. When the mitochondria is placed in an acidic solution, hydrogen ions are released. The ions go through ATP synthase, combining ADP and phosphate, forming an ATP molecule.

28. Genetic testing reveals that baby Helen has a defective gene that results in the defective production of one of the proteins in the electron transport chain. Because of faulty instructions in her DNA, one of the proteins in her ETC is mis-shapen, and therefore it cannot perform its function as efficiently. Baby Helen is “failing to thrive” as she is having a hard time gaining weight and reaching developmental milestones. Using your knowledge of the ETC and its role in making ATP, explain why you think baby Helen is having the problems described above.

If one of the proteins in the Electron Transport Chain is misshaped, hydrogen ions won't be able to move through the passageway efficiently. Without the hydrogen ions traveling through the protein, ATP synthase cannot occur. Therefore, not all 32 ATP molecules in ATP synthase would be made for baby Helen.

29. Compare the basic transformation of energy during photosynthesis and cellular respiration.

In photosynthesis, light engery becomes chemical energy. Sunlight, water and carbon dioxide are used in photosynthesis producing the chemical energy in glucose, and oxygen. In cellular respiration, chemical energy becomes usuable energy. Glucose and oxygen are used cellular respiration and produces ATP (energy), water, and carbon dioxide.

30. Describe the role of ATP in biochemical reactions. What is ATP used for in your cells? How do your cells get energy out of a molecule of ATP? How is ATP recharged?

ATP is used for all reactions in the cell, such as cell division. To use this energy, you break a bond between a phosphate group. This changes the moecule of ATP to ADP. To recharge the ATP molecule, you need to add one phosphate group to the ADP molecule.